1、查看centos 版本：cat /etc/redhat-release
2、启动服务：systemctl start firewalld.service如果服务报错Failed to start firewalld.service: Unit is masked执行systemctl unmask firewalld.service再启动systemctl start firewalld.service
3、关闭服务：systemctl stop firewalld.service
5、显示服务的状态：systemctl status firewalld.service
7、查看已启动的服务列表systemctl list-unit-files|grep enabled
